US20240034192A1 - Balancing method - Google Patents

Balancing method Download PDF

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Publication number
US20240034192A1
US20240034192A1 US18/256,322 US202118256322A US2024034192A1 US 20240034192 A1 US20240034192 A1 US 20240034192A1 US 202118256322 A US202118256322 A US 202118256322A US 2024034192 A1 US2024034192 A1 US 2024034192A1
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United States
Prior art keywords
cells
stand
slave device
sub
cell
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Pending
Application number
US18/256,322
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English (en)
Inventor
Ana-Lucia Driemeyer Franco
Pierre-Mikael VIOLLIN
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Ampere Sas
Original Assignee
Renault SAS
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Assigned to RENAULT S.A.S reassignment RENAULT S.A.S ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VIOLLIN, Pierre-Mikael, DRIEMEYER FRANCO, ANA-LUCIA
Publication of US20240034192A1 publication Critical patent/US20240034192A1/en
Assigned to AMPERE S.A.S. reassignment AMPERE S.A.S. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RENAULT S.A.S.
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/22—Balancing the charge of battery modules
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/90—Vehicles comprising electric prime movers
    • B60Y2200/91—Electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/90—Vehicles comprising electric prime movers
    • B60Y2200/92—Hybrid vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • the invention relates to a method for balancing the cells of a battery of electric accumulators.
  • the invention relates to management of the batteries of electric or hybrid vehicles.
  • An electric, hybrid or even rechargeable hybrid vehicle comprises a battery of electric accumulators that is formed of a high number of cells in series and/or in parallel.
  • SOH state of health
  • any difference in state of charge between cells mounted in series is a limiting parameter since the total usable capacity of the battery is directly impacted. Specifically, the greater the difference in charge between the cells, the more the total usable capacity of the battery decreases. This therefore has a negative impact on the range of the electric vehicle.
  • Balancing is carried out by a battery management system (BMS), directly and independently.
  • BMS battery management system
  • dissipative balancing also called “passive” balancing
  • passive balancing consists in balancing the states of charge of the cells by discharging the cells into a resistor to a target state of charge, in general the state of charge of the cell having the lowest SOC.
  • the balancing circuit When the balancing circuit is well dimensioned, i.e. when the balancing current is sufficient, and when the balancing strategy is used regularly, the dispersion in state of charge between cells is kept lower than a given threshold.
  • This threshold depends inter alia on the precision of measurement of the cell voltages.
  • this balancing strategy can be activated only during operation of the vehicle.
  • asleep what is meant is a state in which the motor vehicle is shut down and in which its computers are shut down.
  • the objective is further not to draw power from the on-board supply grid of the vehicle, since it is necessary to carry out this operation with all the computers, including the BMS, asleep.
  • the invention aims to provide a stand-alone and optimized cell-balancing solution that works when the motor vehicle is asleep and that does not cause overheating of the battery, or of its management units, nor over-discharging of the cells.
  • a method for controlling balancing of the cells of a battery of electrical accumulators of an electrical system comprising a main management unit and a plurality of stand-alone slave devices,
  • Said method comprises, for each stand-alone slave device of each sub-group of cells, steps consisting in:
  • the method thus makes it possible to balance the battery cells when the main management unit is off, by discharging the cells to be balanced into their associated resistor, this allowing optimal balancing to be obtained while ensuring that the balancing does not cause overheating of the slave devices, and especially of the balancing resistors, through selection of non-adjacent resistors, and while avoiding any over-discharging, especially through definition of a predetermined threshold value defining whether a cell is eligible for balancing.
  • the resistors associated with said cells are identified by the stand-alone slave device by a numerical identifier, the resistors being arranged in each sub-group so that two adjacent resistors have a numerical identifier of different parity, characterized in that that the selecting step is preceded by an identifying step in which the parity value of the resistor associated with said cell having the greatest amount of electric charge to be balanced is identified,
  • candidate cells are selected for balancing by selecting the cells associated with a resistor of the same parity as the resistor of the cell to be balanced, and hence resistors not adjacent to the resistor of the cell to be balanced are detected in a relatively simple manner. This allows a selecting method that is fast and relatively simple from an algorithmic point of view to be obtained.
  • said predetermined threshold value is determined depending on a maximum duration of stand-alone operation of the stand-alone slave devices multiplied by a maximum balancing current between two cells. This allows a relevant and relatively optimal threshold value to be obtained.
  • the invention is not limited to such a calculation and according to one alternative the predetermined threshold value may be set in a step prior to the implementation of the method.
  • the invention also relates to a main management unit of an electrical system comprising a battery of electric accumulators and a plurality of stand-alone slave devices,
  • said cells of said battery being separated into a plurality of sub-groups, each associated with one stand-alone slave device, and said cells of each sub-group being arranged beside one another,
  • the invention also relates to an electrical system comprising a battery of electrical accumulators, a plurality of stand-alone slave devices, and a main management unit such as described above, said unit being configured to implement the method such as described above.
  • the invention also relates to a motor vehicle comprising an electrical system such as described above.
  • FIG. 1 is a schematic view of an electrical system according to the invention.
  • FIG. 2 is a flowchart of one implementation of the method according to the invention.
  • FIGS. 1 and 2 relate to the same first embodiment of the invention, they will be discussed simultaneously.
  • An electrical system 1 of an electric, hybrid or rechargeable hybrid vehicle comprises a battery 2 of electrical accumulators.
  • This battery 2 of electric accumulators is made up of a plurality of distinct cells 20 - 35 , which are arranged in the vicinity of one another.
  • the cells are in this example numbered so that they may also be identified by a parity value, even cells being associated with an even number, and odd cells being associated with an odd number, the cells thus being aligned so that an even cell alternates with an odd cell.
  • the cells are divided into two sub-groups 201 and 202 , the first sub-group 201 comprising cells 20 to 27 , and the second sub-group comprising cells 28 to 35 .
  • each sub-group 201 , 202 comprises 8 cells
  • the invention is not limited to this single example.
  • a sub-group may comprise between 6 and 12 batteries, but a person skilled in the art could equally well create smaller or larger sub-groups, although the effectiveness of the invention might be decreased as a result.
  • Each sub-group 201 , 202 of cells is associated with one stand-alone slave device 4 , 4 ′, which in this embodiment is an application-specific integrated circuit (ASIC).
  • ASIC application-specific integrated circuit
  • the stand-alone slave devices 4 , 4 ′ are not limited to this single type of component. They may also be, by way of non-limiting example, field-programmable gate arrays (FPGAs), a microcontroller, a microprocessor.
  • FPGAs field-programmable gate arrays
  • microcontroller a microcontroller
  • microprocessor microprocessor
  • the stand-alone slave devices 4 , 4 ′ further comprise, for each cell, a controlled switch 60 - 75 and a resistor 80 - 95 , for example a resistor of resistance comprised between 50 ohms and 150 ohms, in this embodiment a resistance of 100 ohms.
  • a circuit is thus present in the associated slave device 4 , 4 ′ allowing the cell 20 - 35 to be balanced.
  • This circuit comprises a resistor 80 - 95 and a controlled switch 60 - 75 in series.
  • the cell 20 - 35 When the cell 20 - 35 is being balanced, it discharges into its associated resistor 80 - 95 , this discharging resulting in balancing. In other words, the charge of cell 20 - 35 is reduced through discharging into the associated resistor 80 - 95 , in order to bring its charge back to a balanced charge level. However, this situation leads to notable heating of the associated resistor 80 - 95 .
  • the conventional arrangement of resistors 80 - 95 in the stand-alone slave devices 4 , 4 ′ is an arrangement in a row, that is to say they are spatially aligned beside one another in each of the stand-alone slave devices in question, as shown in FIG. 1 .
  • Each stand-alone slave device 4 , 4 ′ is configured to control the switches 60 - 67 and 68 - 75 associated with each of their cells 20 - 27 and 28 - 35 , respectively.
  • the stand-alone slave device 4 , 4 ′ thus allows the associated cell 20 - 35 to be balanced with respect to another cell 20 - 35 of the same sub-group 201 , 202 .
  • the electrical system 1 comprises a main management unit 5 that controls the operation of the stand-alone slave devices 4 , 4 ′.
  • the main management unit 5 is the master unit of the stand-alone slave devices 4 , 4 ′.
  • the main management unit 5 may for example be an on-board computer or any other computing device able to communicate and receive measurement information from the battery cells and to control the commands given to the stand-alone slave devices 4 , 4 ′.
  • This main management unit 5 and the stand-alone slave devices 4 , 4 ′ form an assembly generally known as a battery management system (BMS).
  • BMS battery management system
  • the main management unit 5 implements a method 30 for controlling the stand-alone slave devices 4 , 4 ′ to balance the cells 20 - 35 of the battery 2 , so that it may be shut down when this balancing is actually carried out.
  • This method 30 is in this embodiment triggered when the main management unit 5 receives a shutdown or standby order.
  • the main management unit 5 implements the following method 30 in order to organize balancing of the batteries during its period of shutdown or sleep.
  • This method 30 comprises steps that are implemented in parallel or in series for each sub-group 201 , 202 .
  • a step 301 of receiving, for each cell 20 - 35 associated with said stand-alone slave device 4 , 4 ′, the amount of electric charge to be balanced is first implemented.
  • the cell having the greatest amount of electric charge to be balanced is determined 302 .
  • the cells of the same sub-group allowing voltage to be balanced with said determined cell 302 are then selected 304 .
  • steps of selecting cells based on the parity value of their associated resistors 80 - 95 are implemented. Specifically, this solution makes it possible to be relatively rapid from the point of view of the algorithm to be implemented.
  • the cells 20 - 35 are each associated with one resistor 80 - 85 the numerical reference of which has the same unit.
  • cell 21 is associated with a resistor 81 , both of odd values.
  • a step of identifying the parity value of the resistor 80 - 95 of the cell determined in the preceding step 302 is initially carried out.
  • each cell 20 - 35 and each associated resistor 80 - 95 of the sub-group 201 , 202 are associated with a numerical value, for example its numerical reference in the example, and it is checked whether the remainder of Euclidean division of this value by 2 is zero, in which case the number is even, or non-zero, in which case the number is odd.
  • a parity indicator for example a binary value, will possibly be associated with each cell, so as not to have to recompute the parity of the cell a number of times.
  • this first example of embodiment is based on parity selection
  • resistors of value congruent modulo N>2 with the resistor of the cell determined in step 302 .
  • resistors of value congruent modulo N>2 For example, it is especially possible to select a resistor separated by two other resistors, or in other words one resistor in three, and therefore resistors of values congruent modulo 3 with the resistor determined in step 302 .
  • a set of candidate cells for balancing comprising all the cells of the sub-group the associated resistor 80 - 95 of which has a parity identical to the parity determined for the resistor of the cell to be balanced, is then selected 304 .
  • Cells for which the charge to be balanced is less than a predetermined threshold value are then excluded 305 from this set of candidate cells.
  • the predetermined threshold value is computed by calculating the product of the maximum operating time of the stand-alone slave devices 4 , 4 ′ multiplied by the maximum balancing current.
  • the maximum time is for example defined to lie in a range extending from one hour to two hours—it is for example a duration of 3640 seconds—and the maximum balancing current for example lies in a range of values extending from 20 mA to 100 mA.
  • the invention is however not limited to this precise order of implementation of the selecting and excluding steps 304 , 305 . Provision could for example be made for all the cells having a charge to be balanced less than the predetermined threshold value to first be excluded 305 , then for the cells having a parity identical to the parity determined for the cell to be balanced to be selected among all the remaining cells. The selection result would nonetheless be the same.
  • a step of commanding the stand-alone slave device associated with this sub-group 201 , 202 is then implemented, so that it balances the cell having the greatest amount of electric charge to be balanced with the cells of said selection of candidate cells, by controlling the associated controlled switches.
  • the main management unit 5 is shut down or put to sleep.
  • each of the stand-alone slave devices 4 , 4 ′ which for example are ASICs, to be individually controlled so that they drive the configured controlled balancing switches 60 - 75 for a determined time, which is either predetermined or configurable as required.
  • the method is further configured so as:
  • cells of the same sub-group 201 , 202 are selected 304 , in order to balance voltage with said determined cell 302 , using a technique other than the parity selection of the first embodiment.
  • all the cells not adjacent to the cell to be balanced are selected.
  • the associated stand-alone slave device may comprise any type of data organization permitting such a determination—for example, a map of the arrangement of cells in the sub-groups 201 , 202 may be stored in memory.
  • Such a method for controlling balancing of battery cells in “sleep” mode may be applied to any other system for monitoring multi-cell batteries in order to limit the imbalance between cells and thus preserve autonomy, not only in the automotive field but also in any other field in which implementation involves electronics.
  • the method may also be implemented in stationary systems in the case where the supply of the battery management unit of the system is subject to a consumption constraint.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
US18/256,322 2020-12-08 2021-12-06 Balancing method Pending US20240034192A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR2012815A FR3117274B1 (fr) 2020-12-08 2020-12-08 Procédé d’équilibrage
FR2012815 2020-12-08
PCT/EP2021/084327 WO2022122621A1 (fr) 2020-12-08 2021-12-06 Procédé d'équilibrage

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US20240034192A1 true US20240034192A1 (en) 2024-02-01

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US18/256,322 Pending US20240034192A1 (en) 2020-12-08 2021-12-06 Balancing method

Country Status (7)

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US (1) US20240034192A1 (fr)
EP (1) EP4260430A1 (fr)
JP (1) JP2023551804A (fr)
KR (1) KR20230118124A (fr)
CN (1) CN116547883A (fr)
FR (1) FR3117274B1 (fr)
WO (1) WO2022122621A1 (fr)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11411409B2 (en) * 2017-04-28 2022-08-09 Gs Yuasa International Ltd. Management apparatus, energy storage apparatus, and energy storage system
US11173807B2 (en) 2017-06-09 2021-11-16 Ford Global Technologies, Llc Battery charge equalization system timer
KR102173777B1 (ko) * 2017-07-25 2020-11-03 주식회사 엘지화학 마스터 배터리 관리 유닛 및 이를 포함하는 배터리팩
US10983165B2 (en) * 2018-07-09 2021-04-20 Ford Global Technologies, Llc Front end pass switch for battery monitoring circuit
KR102443667B1 (ko) * 2018-10-26 2022-09-14 주식회사 엘지에너지솔루션 밸런싱 장치, 및 그것을 포함하는 배터리 관리 시스템과 배터리팩

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Publication number Publication date
FR3117274B1 (fr) 2022-10-21
JP2023551804A (ja) 2023-12-13
KR20230118124A (ko) 2023-08-10
EP4260430A1 (fr) 2023-10-18
CN116547883A (zh) 2023-08-04
FR3117274A1 (fr) 2022-06-10
WO2022122621A1 (fr) 2022-06-16

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